The title slide presents a geotechnical and remedial analysis of the slope failure at Bukit Nanas, Malaysia. It draws insights from 2015 case studies by Abdullah et al. and Ahmad et al.

Geotechnical and Remedial Analysis

of Slope Failure at Bukit Nanas, Malaysia

Insights from 2015 Case Studies by Abdullah et al. and Ahmad et al.

Source: Abdullah et al. (2015), Ahmad et al. (2015)

This slide introduces a 2015 slope failure event at Bukit Nanas in Kuala Lumpur, Malaysia. Its objective is to analyze the causes, stability, and remedial options, with a focus on enhancing urban slope safety in tropical environments.

Introduction

• 2015 slope failure event at Bukit Nanas, Kuala Lumpur, Malaysia
• Objective: Analyze causes, stability, and remedial options
• Focus: Enhancing urban slope safety in tropical environments

Source: Abdullah et al. and Ahmad et al. (2015 Bukit Nanas case studies)

The slide describes the Bukit Nanas urban hill site, featuring a site map of 45° steep granite slopes covered in highly weathered residual soil with low shear strength. It highlights failure features like tension cracks and debris flow scars, noting high urban risk due to proximity to buildings.

Site Description and Failure Features

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• Site map: Bukit Nanas urban hill, 45° steep granite slopes.
• Granite residual soil, highly weathered, low shear strength.
• Failure features: Tension cracks, debris flow scars.
• Proximity to buildings, high urban risk exposure.

Source: Bukit Nanas 2015 case studies (Abdullah et al., Ahmad et al.)

The slide "Causes of Failure" outlines key factors leading to instability, including heavy rainfall that saturates soil and raises pore pressure, as well as inadequate drainage that worsens water infiltration. It also highlights the risks from shallow weathering zones prone to instability and vegetation loss due to urbanization, which reduces root reinforcement.

Causes of Failure

• Heavy rainfall causing soil saturation and pore pressure rise
• Inadequate drainage exacerbating water infiltration
• Shallow weathering zone prone to instability
• Vegetation loss and urbanization reducing root reinforcement

Source: Abdullah et al. (2015)

The slide details a geotechnical investigation with field work involving five boreholes (BH1-5) to 10-20m depths, including SPT for relative density and CPT for stratigraphy and strength. Laboratory tests confirmed granular silty sands with clay lenses in loose to medium dense conditions, yielding parameters like c'=10kPa, φ'=28°, and γ=18kN/m³ (Ahmad et al.).

Geotechnical Investigation

Source: Ahmad et al. (2015)

The Slope Stability Analysis Workflow outlines four phases: defining soil profile and inputs (1-2 weeks by Geotech Engineer), mesh and model setup (1 week using software like SLOPE/W), running analysis to compute Factor of Safety (FOS) via Bishop or Morgenstern-Price methods (2-3 days by Geotech Engineer), and interpreting results targeting FOS >1.5 with sensitivity analysis (1 week by Project Lead). This structured process ensures comprehensive evaluation of slope stability under various loads and conditions.

Slope Stability Analysis Workflow

Source: Bukit Nanas Slope Failure (Abdullah et al., 2015; Ahmad et al., 2015)

The slide compares two remedial options for slope stabilization, both using soil nails at a height of 12m. Option 1 (RC Wall + Soil Nail) offers higher FOS of 1.8 with high stability and durability, while Option 2 (Crib Wall + Soil Nail) has FOS of 1.6 and is eco-friendly and permeable.

Results and Comparison

Source: Based on Abdullah et al. (2015) & Ahmad et al. (2015)

The slide summarizes remediation options for Bukit Nanas slope failure, with Option 2 (Crib Wall + Soil Nail) at $1.8M and 12 months being the most cost-efficient (FOS >1.5), compared to Option 1 (RC Wall + Soil Nail) at $2.5M and 18 months. It recommends preventive measures like enhanced drainage, piezometer monitoring, and vegetation stabilization, emphasizing integrated geo-remediation and proactive monitoring to secure slopes and build resilient urban futures.

Cost, Duration, Preventive Measures & Conclusions

<h3>Cost & Duration Summary</h3><table style='width:100%; border-collapse:collapse; font-size:0.9em;'><tr><th>Option</th><th>Cost</th><th>Duration</th></tr><tr><td>1: RC Wall + Soil Nail</td><td>$2.5M</td><td>18 months</td></tr><tr><td>2: Crib Wall + Soil Nail</td><td>$1.8M</td><td>12 months</td></tr></table><h3>Preventive Measures</h3><ul><li>Enhanced surface/sub-surface drainage systems</li><li>Continuous piezometer monitoring</li><li>Vegetation stabilization</li></ul><h3>Key Insights</h3><ul><li>Option 2: Optimal cost-efficiency (FOS >1.5)</li><li>Integrated geo-remediation essential for tropical urban slopes</li><li>Proactive monitoring prevents recurrence</li></ul><p><strong>Closing:</strong> Secure slopes, safeguard futures.</p><p><em>Call-to-Action:</em> Implement integrated solutions for resilient urban geohazards.</p>

Optimal Remediation for Bukit Nanas Slope Failure

Source: Abdullah et al. (2015); Ahmad et al. (2015)